Boston Marathon bombing victims

Boston Marathon bomber victims

Two explosives went off near the finish line of the Boston Marathon April 15, 2013, killing three and wounding 264 people. Sean Collier, 26, an MIT campus police officer, was fatally shot in his patrol car April 18th by the Boston bombers. The three killed by the explosions were 29-year-old Krystle Campbell (left), 8-year-old Martin Richard (center) and 23-year-old Lu Lingzi (right).

Tamerlan Tsarnaev, 26, one of the two brothers responsible for the attacks, was killed soon after. Dzhokar Tsarnaev, 21, was found guilty April 8, 2015 of multiple counts including conspiracy to use a weapon of mass destruction in their deaths and for injuring 264 others at the Boston Marathon's crowded finish line on April 15, 2013. The unanimous decision to sentence him to death was announced May 15, 2015.

Credit: WBZ

Boston Marathon bombing victims

Lu Lingzi was a graduate student from China studying at Boston University when she was killed.

Lingzi, in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo

Credit: via Facebook

Boston Marathon bombing victims

Lu Lingzi in an undated personal photo

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell, of Medford, Mass., went with her best friend to take a pictures at the Boston Marathon.

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Krystle Campbell in an undated personal photo.

Credit: via Facebook

Boston Marathon bombing victims

Martin Richard in an undated personal photo.

Martin, of Dorchester, Mass., was with his family near the finish line waiting for his father to complete the marathon.

Credit: Lucia Brawley via Facebook

Boston Marathon bombing victims

Martin Richard in an undated personal photo.

Credit: Family Photo

Boston Marathon bombing victims

Martin Richard in an undated personal photo.

Credit: Cheryl Richard Dipesa/CBS

Killed by Boston bombers

Massachusetts Institute of Technology (MIT) police officer Sean Collier, 27, was ambushed and shot dead a few days after the Boston Marathon bombings, April 18, 2013. He was the last casualty of the Boston bombers.

Credit: WBZ-TV

Killed by Boston bombers

Investigators came to believe that MIT Police Officer Sean Collier was killed by the Tsarnaev brothers because the two Boston bombers wanted to take his gun.

Credit: .

Killed by Boston bombers

Andrew Collier, left, puts his hand on his brother, Robert, after delivering the eulogy at a memorial service for their brother, slain Massachusetts Institute of Technology campus officer, Sean Collier, at MIT in Cambridge, Massachusetts, April 24, 2013.